<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Promise</title>
</head>
<body>
    <script>
        //实例化Promise对象
        const p = new Promise(function(resolve,reject){
            setTimeout(function(){
                // let data = '用户数据';
                //resolve
                // resolve(data);

                let err='数据读取失败';
                reject(err);
            },1000)
        })
        //调用promise对象的then方法
        p.then(function(value){
            console.log(value)
        },function(reason){
            console.error(reason)

        })
    </script>
</body>
</html>